It does not seems to work to install SP2 for a collection of solutions that are not suites.
For example, we have an installation of Inventory, Monitoring, Software Management, etc. but without Patch Management, Analytics and Deployment Solution.
Although you can select to install SP2 solutions, it invariably comes up with an error at the Readiness Check, to say that you have not selected all solutions. There aren't any left that we have not selected!
I can see a workaround to install a suite and then uninstall the solutions that are not required, but I wondered if there is a proper way to do this.
Anthony